Migration Research Foundation - McGill Bird Observatory - Photo Library

McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Slate-coloured Junco (Junco hyemalis)

Seasonal status at MBO:

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

common

fairly common

uncommon

rare

occasional

no records

QUICK TIPS:

1) Look at the back and head - AHY/ASY males are dark gray with little or no brown, HY/SY males and AHY/ASY females are medium gray with brown especially on the back, and HY/SY females are brownish-gray and paler than other ages/sexes

2) Examine the greater coverts - HY/SY birds often have a conspicuous moult limit among the greater coverts with retained brown outer coverts contrasting with replaced gray inner coverts, while AHY/ASY birds have uniform greater coverts

3) Look at the primary coverts - on HY/SY birds they are brownish-gray and contrasting with the gray replaced inner greater coverts, while on AHY/ASY birds they are uniform in colour and wear with the greater coverts

4) Check the tail - on HY/SY birds the outer rectrices are narrow and tapered, while on AHY/ASY birds they are broad and rounded; note that the amount of white does not appear to reliably correspond to age or sex

5) In fall and winter, look at the iris under good light - it is grayish-brown on HY/SY birds, and reddish on AHY/ASY birds

Note: there are several subspecies of Dark-eyed Junco in North America; the descriptions provided are for the eastern race, Slate-coloured Junco, but comments regarding moult limits and feather shape/condition are likely broadly applicable to other races too.

Ageing and sexing guidelines:

January - July:

ASY - M Dark gray above, entirely lacking brown; rectrices broad and rounded.
ASY - F Gray above, with some brown on the back. Wing entirely gray; rectrices broad and rounded.
SY - M Gray to dark gray above, with little or no brown on the back. Primary coverts tinged brown; rectrices narrow and tapered.
SY - F Gray above, with some brown on the back. Primary coverts tinged brown; rectrices narrow and tapered.

June - December:

AHY - M Dark gray above, with little brown on the back; wing uniformly gray; rectrices broad and rounded.
AHY - F Gray above, with extensive brown on the back. Wing entirely gray; rectrices broad and rounded.
HY - M Gray to dark gray above, with a fair amount of brown on the back. Primary coverts tinged brown; moult limits may appear among the greater coverts; rectrices narrow and tapered.
HY - F Gray above, with some brown on the back. Primary coverts tinged brown; moult limits may appear among the greater coverts; rectrices narrow and tapered.

Ageing and sexing details:

after-second-year male

ASY males are uniformly dark gray above, without any brown body feathers.

The wing of ASY juncos is uniformly gray, with no contrast in colour or condition between any feather tracts.

ASY birds have broad and rounded tails. The amount of white on the outer three rectrices tends to be most extensive on ASY males, but there is considerable variation among and between races, and this feature cannot be used alone to age or sex individuals.

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after-second-year female

There is some overlap between SY males and ASY females in overall appearance, but ASY females tend to be somewhat paler gray, and with more brown on the back. Age can usually be easily determined by looking at the wing and/or tail.

Photo by Marcel Gahbauer, April 2006

ASY juncos have a uniformly gray wing, with no contrast in colour or condition between feather tracts.

Photo by Marcel Gahbauer, April 2006

Rectrices are broad and rounded, usually showing relatively little wear even by spring.

Photo by Marcel Gahbauer, April 2006

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second-year male

There is some overlap between SY males and ASY females in overall appearance, but SY males tend to be somewhat darker gray, and with less brown on the back. Age can usually be easily determined by looking at the wing and/or tail. Sometimes, as in the photo below, the unreplaced juvenile greater alula is visibly more brown than adjacent feathers and is a good indicator of an SY bird.

Photo by Marcel Gahbauer, January 2006

Juncos can easily be aged as SY by their wing molt. The primary coverts are usually brownish or brownish-gray, contrasting with the overall gray tone of the wing. In some individuals, as in the photo below, there is also a more conspicuous molt limit among the greater coverts, with the outer four retained juvenile coverts showing a brownish edge and white tips, in contrast to the replaced entirely gray inner coverts.

Photo by Marcel Gahbauer, January 2006

The tail is quite reliable for ageing juncos, with SY birds having narrower and more tapered rectrices than ASY birds.

Photo by Marcel Gahbauer, January 2006

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second-year female

SY females are paler than all other age/sex combinations. They are usually medium gray on the upper breast and back, mixed with some pale brown, sometimes leading to a bit of a pinkish tone.

Photo by Marcel Gahbauer, April 2006

The tail is quite reliable for ageing juncos, with SY birds having narrower and more tapered rectrices than ASY birds. The amount of white on the outer three rectrices tends to be least extensive on SY females, but there is considerable variation among and between races, and this feature cannot be used alone to age or sex individuals.

Photo by Marcel Gahbauer, April 2006

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after-hatch-year male

ASY males are uniformly dark gray above, usually with only a bit of brown on the back.

Photo by Marcel Gahbauer, October 2005

The wing of AHY juncos is uniformly gray, with no contrast in colour or condition between any feather tracts.

Photo by Marcel Gahbauer, October 2005

AHY birds have broad and rounded tails. The amount of white on the outer three rectrices tends to be most extensive on AHY males, but there is considerable variation among and between races, and this feature cannot be used alone to age or sex individuals.

Photo by Marcel Gahbauer, October 2005

RETURN TO AGE/SEX OVERVIEW

after-hatch-year female

There is some overlap between HY males and AHY females in overall appearance, but AHY females tend to be somewhat paler gray, and with more brown on the back and upper breast. Age can usually be easily determined by looking at the wing and/or tail.

Photo by Marcel Gahbauer, October 2005

AHY females have uniformly gray primary and greater coverts, though there may be some brownish edging on inner greater coverts.

Photo by Marcel Gahbauer, October 2005

AHY juncos have broad and rounded tails. The amount of white averages greater on AHY birds than on HY individuals, but not reliably so.

Photo by Marcel Gahbauer, October 2005

RETURN TO AGE/SEX OVERVIEW

hatch-year male

There is some overlap between HY males and AHY females in overall appearance, but HY males tend to be somewhat darker gray, especially in the face, and with less brown on the back and upper breast. Age can usually be easily determined by looking at the wing and/or tail.

Photo by Marcel Gahbauer, October 2005

Juncos can easily be aged as HY by their wing molt. The primary coverts are usually brownish or brownish-gray, contrasting with the overall gray tone of the wing. In some individuals, there is also a more conspicuous molt limit among the greater coverts, with one to several outer retained juvenile coverts showing a brownish edge and white tips, in contrast to the replaced entirely gray inner coverts.

Photo by Marcel Gahbauer, October 2005

The tail is quite reliable for ageing juncos, with HY birds having narrower and more tapered rectrices than AHY birds.

Photo by Marcel Gahbauer, October 2005

RETURN TO AGE/SEX OVERVIEW

hatch-year female

SY females are paler than all other age/sex combinations. They are typically more brown than gray on the back, with an pale upper breast that is a mixture of light gray and brown. Colouration varies by subspecies; the amount of brown on the upper breast of the third bird below is suggestive of the cismontanus subspecies.

Photo by Marcel Gahbauer, October 2005

Photo by Marie-Anne Hudson, McGill Bird Observatory, October 2007

Juncos can easily be aged as HY by their wing molt when it is readily visible. The primary coverts are usually brownish or brownish-gray, contrasting with the overall grayish wing (though on HY females there if often a brown tone to the wing overall, as in the photos below). In some individuals, there is also a more conspicuous molt limit among the greater coverts, with one to several outer retained juvenile coverts showing a brownish edge and white tips, in contrast to the replaced entirely gray inner coverts. The first photo below shows these contrasts very clearly, while the second illustrates the opposite end of the spectrum where they are very subtle.

Photo by Marie-Anne Hudson, McGill Bird Observatory, October 2007

Photo by Marcel Gahbauer, October 2005

The tail is quite reliable for ageing juncos, with HY birds having narrower and more tapered rectrices than AHY birds. The amount of white on the outer three rectrices tends to be least extensive on HY females, but there is considerable variation among and between races, and this feature cannot be used alone to age or sex individuals.

Photo by Marcel Gahbauer, October 2005

Photo by Marie-Anne Hudson, McGill Bird Observatory, October 2007

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